Note: only 'src' parameter is mandatory. Array of 'options' is the same you use for image options in Html::img(). If both 'og' (OpenGraph) and 'md' (schema.org) configuration arrays are empty - you may not declare them at all. You can to disable one of them (they are both enabled by default) - e.g. 'md' => ['enable' => false].

Properties like 'width' and 'height' set explicitly in 'og' and 'md' configuration arrays, passed to widget, have priority.
If no such options were set, widget attempts to extract properties from image 'options' array.